Alarm switch



w. (5. EDDY 2,439,509

ALARM SWITCH Filed Feb. 11, 1946 Patented a. 13. 1948 2,439,509

UNITED STATES PATENT OFFICE ALARM SWITCH William C. Eddy, Michigan City, Ind., aseignor to Television Associates, Inc., Chicago, 111., corporation of Illinois Application February 11, 1946, Serial No. 646,752

This invention is directed -t0,a switch for use in conjunction with a refrigerating apparatus.

The principal object of this invention is to provide a switch adapted to be placed in the cooling compartment of a refrigerating apparatus 5 be piled up therein as shown at It. The cold for giving an alarm when the temperature therein storage unit may be provided with an access openrises to a predetermined value and wherein the ing with a suitable cover l8. After the frozen usual thermostatic elements are eliminated. foodstuffs are placed in the cold storage unit, the

This invention is particularly useful in quick alarm switch l0 may be set on top of them and, freeze and cold storage units wherein foodstuffs preferably, the alarm switch i0 is located adjaand the like are frozen and stored. Usually large cent the top of the unit, as shown in Fig. 2 where quantities of foodstuffs and the like are stored in the temperature of the unit is usually the such units and if the temperature therein should warmest. rise to values where the foodstuffs would become The alarm switch l0 may comprise a base plate unfrozen, great damage thereto would result. 5 I3 carrying a bifurcated support I! to which an The switch of this invention, being foolproof in arm or lever 23 is pivoted by a pivot pin 2|. The operation, will give an alarmbefore this dangerlever carries a cup 22 provided with an openous condition can occur and thus permit saving ing 23 in the bottom thereof. When the cup 22 of the foodstuffs and the like stored in the units is empty, the weight of the lever 20 is such that from damage. 20 it is maintained in the position shown in Fig. 1.

In carrying out this object of the invention the When, however, frozen material such as an ice switch comprises electrical contacts for controlcube 24 is placed in the cup 22, the weight of the ling the alarm, a pivoted lever for normally closlever 20 is overbalanced by the weight of the ice ing the contacts to give the alarm, and a cup cube 24 to hold the lever 20 in the position shown carried by the lever and provided with an open- 25 in Fig. 2. ins therein to receive frozen material for holding The lever 20 acts as one electrical contact the contacts open, the arrangement being such engaging and disengaging a stationary electrical that upon rise in temperature in the refrigerating contact 23 carried by a block of insulating mateapparatus, the frozen material will melt and drain rial 21. The contact 23 is maintained in the block through the opening to permit closing of the con- 21 by a screw 23. A screw 23 extending through tacts. The frozen material may be in the form an insulating washer 3|! in the base plate l8 screws of an ice cube and in the making of the ice cube into the contact 28 so that the screw 29 is elecvarious amounts of salt or other material for trically connected to the contact 28. A metal lowering the melting point thereof may be utistrip 3| electrically connects the screw 29 to a lized. In this way the melting point of the frozen 85 screw 32 which passes through insulating washers material may be determined and hence the tem- 33 and 34. A nut 35 clamps the strip 3! in place perature of the refrigerating apparatus at which and a nut 33 provides means for securing a wire the alarm will be given also determined. in electrical connection with the screw 32.

The switch may be a self-contained unit con- The base plate l3 may be provided with a clip taining the battery and alarm or the electrical 33 for carrying a battery 33 having terminals 40 source and alarm may be located exteriorly of and 4i. The base plate 18 may also carry an the refrigerating apparatus. audible alarm 42 having operating coils 43 and Other objects and advantages will become ap- 44. The base plate It being made of metal is parent to those skilled in the art upon reference electrically connected to the lever 23 through the to the accompanying specification, claims and 45 pivot pin 2! and support I! and is providedwith drawing, in whicha screw 45 for receiving a wire. The screw 32 Fig. 1 is a perspective view of one form of the and hence the stationary contact 23 are conalarm switch of this invention; nected by a wire 41 to the terminal 4| of the Fig. 2 is a partial sectional view through the battery and the screw 45 is connected by a wire cold storage compartment ofaquick freeze or cold 48 to the operating coils of the audible alarm storage unit showing the alarm switch located 42, which in turn are connected :by a wire 49 to therein: the other battery terminal 43. The electrical Fig. 3 is an enlarged sectional view taken subwiring connections are schematically shown in stantially along the line 3-3 of Fig. 1; Fig. 5, the arrangement being such that when the Fig. 4 is a plan view of a, modified form of the lever 23 engages the stationary contact 26, the alarm switch; audible alarm 42 is energized and when the lever Fig. 5 is a schematic wiring diagram. 20 disenga'ges the contact 26 the audible alarm The alarm switch is generally designated at It is deenergized. The battery and alarm mounted and it may be located in a cold storage comparton the base i3 may be enclosed in a suitable ment ll of a quick freeze and cold storage unit housing II;

3 Claims. (Cl. 200-142) generally designated at l2. The cold storage unit may be of conventional form having side walls l3 and I4 made of insulating material. The frozen articles to be stored in the compartment H may The frozen material such as the ice cube 2% may include salt or other material for lowering the melting point thereof and by predeterminlng the amount of salt or other material placed therein, the melting temperature of the frozen material 24 may be predetermined. In thisway the temperature at which the alarm may be sounded may be predetermined.

When the cold storage unit is packed with the frozen foodstuffs IS, the alarm switch I is placed therein with the frozen material 25 in the cup 22, as shown in Fig. 2. If something should go wrong with the refrigerating apparatus causing the temperature in the cold storage unit to rise to a dangerous point, the frozen material 28 in the cup 22 will melt at the predetermined temperature value and will drain through the opening 23 in the bottom of the cup 22. When this occurs the weight of the lever 20 causes it to engage the contact 26 to sound the audible alarm 42, thereby indicating that proper temperature conditions are not being maintained in the cold storage unit. Having been appraised of this condition a person may then check the unit in adequate time and correct the default in the unit without causing any serious damage to the frozen foodstuffs contained therein,

A slightly modified arrangement is shown in Fig. i. In this arrangement the battery 39 and.

the audible alarm 42 are disassociated from the base plate l8 and may be located outside of the cold storage unit 12. Wires 52 may connect the terminals 32 and 45 of the alarm switchto the alarm and the source of electrical energy outside of the cold storage unit.

While for purposes of illustration two forms this invention have been disclosed, other forms thereof may become apparent to those skilled in the art upon reference to this disclosure and, therefore, this invention is to be limited only by the scope of the appended claims and prior art.

I claim as my invention:

1. A switch adapted'to be placed in a refrigerating apparatus for giving an alarm upon rise in temperature in the refrigerating apparatus to a predetermined value comprising, electrical contacts for controlling the alarm, a pivoted lever for normally closing the contacts to give the alarm, and a cup carried by the lever and for normally closing the contacts to give the alarm, and a cup carried by the lever and pro- VldEdiWlth an opening therein to receive frozen material'for holding the contacts open, the arrangement being such that upon rise in temperature in the refrigerating apparatus to the predetermined value, the frozen material will melt and drain through the opening to permit closing of the contacts. 1

3. A switch adapted to be placed in a refrigerating apparatus for giving an alarm upon rise in temperature in the refrigerating apparatus to a predetermined value comprising, electrical contacts for controlling the alarm, a pivoted lever for normally closing the contacts to give the alarm, and a cup carried by the lever and provided with an opening therein to receive frozen material, having a desired predetermined melting point, for holding the contacts open, the arrangement being such that upon rise in temperature in the refrigerating apparatus to the predetermined value the frozen material will melt and drain through the opening to permit closing of the contacts.

WILLIAM C. EDDY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Tickell Nov. 17, 1942 

